[OpenSIPS-Users] redirect gives "local ACK found -> dropping it!"

[Jeremy Malcolm]

I have an Asterisk server on a machine with a dynamic IP address.  Attached to this is a DID from a provider which doesn't re-resolve this machine's domain name to its IP when it changes.  So, the DID stops working whenever my IP changes.

To work around this, I have set up opensips on a different server which has a static IP (55.66.77.88), and I have given the DID provider its SIP address rather than the dynamic IP machine's address (11.22.33.44).  All that the opensips server needs to do is to forward everything to the machine with the dynamic IP.

I came up with this routing configuration based on one I saw online, which I thought would work:

route{
	
	if (method=="REGISTER") {
		log("REGISTER");
		sl_send_reply("200", "ok");
		return;
	};
       rewritehost("11.22.33.44");
	append_branch("sip:user at 11.22.33.44");
	sl_send_reply("302", "Redirect");

}

But it doesn't, and here is a snippet from the log:

DBG:core:parse_msg: SIP Request:
DBG:core:parse_msg:  method:  <ACK>
DBG:core:parse_msg:  uri:     <sip:user at 55.66.77.88>
DBG:core:parse_msg:  version: <SIP/2.0>
DBG:core:parse_headers: flags=2
DBG:core:parse_via_param: found param type 232, <branch> = <z9hG4bK4299.497faa.0>; state=16
DBG:core:parse_via: end of header reached, state=5
DBG:core:parse_headers: via found, flags=2
DBG:core:parse_headers: this is the first via
DBG:core:receive_msg: After parse_msg...
DBG:core:receive_msg: preparing to run routing scripts...
DBG:core:parse_headers: flags=8
DBG:core:parse_to_param: tag=61ae7837698e5c9f3ea027df6cb50162.41f5
DBG:core:parse_to: end of header reached, state=29
DBG:core:parse_to: display={}, ruri={sip:user at 55.66.77.88:5060}
DBG:core:get_hdr_field: <To> [83]; uri=[sip:user at 55.66.77.88:5060] 
DBG:core:get_hdr_field: to body [<sip:user at 55.66.77.88:5060>]
DBG:sl:sl_filter_ACK: local ACK found -> dropping it!

So as you can see, the rewriting doesn't seem to be happening (unless I'm misunderstanding the log).  Also, Googling for "local ACK found -> dropping it!" wasn't very illuminating.  Am I missing something obvious?

Thanks!

--
Jeremy Malcolm PhD LLB (Hons) B Com
Internet and Open Source lawyer, consumer advocate and geek
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